How Does Air Conditioning Work? (AC)

Simplified Explanation of How Air Conditioning Works (AC)

We have all enjoyed the cool breeze coming out of an air conditioning vent, but chances are you haven't stopped to consider just how an air conditioner is able to cool down the air inside. What follows is a general overview of the process.

The main components of any air conditioner are a compressor, two sets of coils filled with a refrigerant (generally referred to as Freon), and an expansion valve, all connected in a circular fashion. The Freon, which takes on both liquid and gas forms, follows the following cycle:

Freon gas enters the compressor. The compression process heats the Freon, changing it into a high-pressure hot Freon gas.

The hot Freon gas is released into the first coil. The high pressure causes the gas to move along the expanse of the coil, which is located on the outside of the building. Over the course of this journey, the Freon gas begins to cool as a fan causes the outside air to absorb the heat. The newly-cooled Freon gas converts into cool liquid Freon.

The cool liquid Freon enters the expansion valve, where it is converted back into a cooled Freon gas and released into the second coil. The second coil is located on the inside of the building.

Air from inside the building is blown by a fan against the second coil, which contains the cooled Freon gas. The Freon gas absorbs the heat from the air, causing the air to cool and the Freon gas to start to heat up again. The newly-cooled air is released back inside the building.

The process repeats as the Freon gas enters the compressor once again.

Understanding how air conditioning systems work can help us to better utilize them to cool the places we live and work. For example, many people mistakenly believe air conditioning vents blow new cold air into the room in order to lower the overall temperature. Using this logic, opening windows and doors can help to cool a room faster.

However, knowing that air conditioning actually removes heat from air already inside the room can help us to remember to keep the windows and doors closed when the air conditioning is on. Open windows and doors allow for a constant exchange of inside air with outside air. In a closed room, once the air conditioner removes an adequate amount of heat from the air, its job is done for awhile; in an open room, the air conditioner is never done, because new air that requires heat removal is constantly entering.